More on the Delta tunnels JPA

The Metropolitan Water District of Southern California today released the first of three “white papers” on the Delta tunnels, which are supposed to inform MWD board members as the district moves toward a September vote on the project.

Most of what’s in there has been reported previously. But here are a few things I found interesting:

• The JPA. It has already been reported that the state Department of Water Resources and the water contractors were considering forming a joint powers authority to oversee construction. The white paper adds a new justification — the emergency construction work at the Oroville Dam spillway — and a few more details.

“Recognizing DWR staff resources are stretched to an extreme level due to the necessary commitment to complete significant repairs to the Oroville Reservoir spillways as a result of damage during heavy runoff in 2017, there is a need to employ different but proven approaches to pool resources for the design and construction of California WaterFix,” the document says.

In other words: The state has too much on its plate to handle the tunnels, too.

This approach will be controversial, of course. A JPA would effectively give the water contractors who stand to benefit from the tunnels more say in how they will be built. (Then again, they are paying for them.)

Conceptually, the white paper says DWR would retain some level of oversight while the JPA, complete with an executive director and a board of directors, handles the nitty gritty details. A staff would be hired, complete with engineers, accountants, auditors, public relations folks and attorneys, among others.

If something goes kaput, it appears that some changes to the project would have to be approved by DWR while others wouldn’t. Anything more than a 5 percent increase in budget for a major component, for example, would require state approval. Less than 5 percent apparently wouldn’t.

The JPA would have to provide monthly and yearly reports on its progress.

What’s also important in these kinds of deals is the dispute resolution process. What if the water contractors and the state disagree on the best path forward? The white paper lays out a process for an expert panel to help make those decisions. Ultimately, major disputes would come down to the DWR director and the JPA executive director sitting down in a room somewhere and working it out.

The tunnels would be turned over to DWR once they’re finished, and the JPA would cease to exist.

• The cost. Metropolitan’s white paper puts the cost of the project at $15.7 billion. That’s lower than the $17.1 billion that reporters were given by DWR as recently as last week. I’ll ask about this later.

The white paper notes that Metropolitan has a “75 percent confidence level that the project would be completed within the budget estimate.”

The third and final white paper, expected later this summer, will address who pays how much, which may be the thorniest issue of them all.

• The timeline. Metropolitan assumes that construction won’t begin until three years after the project is authorized, which could happen in the coming months. That would mean construction wouldn’t begin until 2020. It would then take about 13 years to build everything. Bottom line, we’d be into the 2030s before it’s over.

• The pumps. This is deep in the weeds. But apparently, when the Sacramento River is flush with water, there are times when the new pumps at the far (south) end of the tunnels can be turned off. I’m not talking about the existing south Delta pumps. I’m talking about the pumps that will be used to pull up water from the tunnels and dump it into Clifton Court Forebay.

So at times, the entire system would be gravity fed — not just the tunnels. Didn’t know that.

• Peat problems? Not according to Metropolitan. The tunnels will be built deep enough to avoid peat soil, which is prone to liquefaction and settlement. Instead the tunnels will be buried in dense deposits of silts, sands and clay layers, the white paper says.

The tunnels will also be deep enough to absorb or dampen vibrations, MWD says. “Induced vibration to structures should be minimal and would not likely be perceptible to the communities on the surface,” the white paper says.

• Why twin tunnels? Why not a single tunnel? Well, a single tunnel would have to be nearly 60 feet in diameter to convey the same amount of water, the white paper says. This would make it among the largest tunnels ever drilled. The proposed 40-foot twin tunnels are plenty big enough, of course, but 40 feet isn’t considered as risky and is more in line with some other major tunnels projects around the world.

• How far along is design? Just 5 to 10 percent. Which perhaps explains why it would take another three years after approval to start building.

• More tests coming. Some Delta property owners fought the state’s efforts to drill for soil samples and conduct other environmental surveys in preparation for tunnels construction. The farmers ultimately lost at the state Supreme Court, but were successful in delaying at least some of the tests.

Today, while 240 drill tests have already been conducted, there are gaps of several miles along the alignment, more work is needed, the white paper says.

“Up to 2,000 additional investigations would be conducted, consisting of borings, cone penetrometer and other physical data collection methods,” the paper says.

Overall, the Met concludes that the tunnels are a “potentially successful project.” The white paper will be discussed at a Metropolitan committee meeting on Monday.

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Blog Author

Alex Breitler

A native of Benicia, he lives in Stockton with his wife, Ann, who forces him to go backpacking in the Sierra Nevada or Trinity Alps at every opportunity. He has been writing mostly about natural resources since 2003, first in Redding and now in ... Read Full